A bearing apparatus for supporting rotary parts has hitherto been, when once incorporated, subjected to none of periodic inspections in many cases, and in such a case it often happened that an interior thereof was inspected for the first time just when inconvenience occurred due to abnormality in temperature. Further, in the case of the bearings for a railway vehicle, a wind turbine, or the like, the bearing apparatus and other portions are decomposed and inspected after being used for a predetermined period of time. It is therefore difficult to predict the inconvenience due to the abnormality in temperature beforehand. An attempt (refer to Japanese Patent Laid-Open Publication No. 2002-130263) in this respect is made to detect the abnormality of the bearing in temperature before the critical inconvenience occurs by measuring a change of the temperature with a temperature sensor attached to the bearing apparatus.